Legambiente: the mouth of the Musone, Aci Trezza and Lake Sabaudia are the most polluted waters in Italia
Of the 391 samples taken by Legambiente volunteers from marine and lake waters across 19 regions, as many as 34 per cent were found to exceed the legal limits for pollution – that is, more than one in three samples
Key points
In Italia, once again this summer of 2026, the sea and lakes are under increasing strain and becoming increasingly vulnerable. This is confirmed by the final report from ‘Goletta Verde’ and ‘Goletta dei Laghi 2026’, Legambiente’s two summer campaigns which monitor the sea and lakes every year. Of the 391 samples taken by Legambiente volunteers from marine and lake waters across 19 regions, as many as 34 per cent were found to exceed the legal limits for pollution – that is, more than one in three samples. Unfortunately, this overall figure is in line with last year’s and shows no sign of improvement. The trend is also negative for lakes, where the 34% recorded in 2026 is the worst figure in the last seven years (from 2020 to 2026). The main factors affecting the health of the sea and lake basins are, first and foremost, inadequate wastewater treatment – a widespread problem in the country which, according to MASE data obtained by Legambiente via a freedom of information request in July 2026, still involves – 514 urban agglomerations, corresponding to over 14 million population equivalents, which discharge waste in a non-compliant manner; and the climate crisis, which is causing the Mediterranean to become increasingly warmer whilst the lakes are drying up.
The data
The detailed data from the two Golette 2026 surveys speak for themselves: once again this year, the mouths of rivers, canals and streams flowing into the sea or lakes have been identified as critical points: of the 188 river mouths sampled, more than half – 54 per cent – were found to be polluted or heavily polluted. Among the chronic and ‘shameful’ sites are the mouth of the Musone, on the Adriatic coast of the Marche region, which has been found to be heavily polluted for the last six years, with the sole exception of 2024; and that of Aci Trezza, in Sicily in the province of Catania, which has exceeded the limits since 2020. Among the lakes, a banner reading ‘What a Shame’ was displayed at Lake Sabaudia, in the province of Latina, where all three samples taken were found to be ‘heavily polluted’. Even in areas far from river mouths or discharge points, water quality is far from ideal: 15 per cent of samples taken directly from the sea or from lakes were found to exceed legal limits, with 5 per cent classified as polluted and 10 per cent as heavily polluted. Another cause for concern is the absence of information signs at river mouths: at 70 per cent of the river mouths monitored during the Goletta Verde campaign alone, no signs prohibiting bathing were found.
Climate crisis and waste
Alongside the issue of pollution and inadequate wastewater treatment is that of the climate crisis, which, on the one hand, is accelerating the tropicalisation of the Mediterranean, the arrival of alien species and coastal erosion, whilst, on the other hand, is causing lakes to dry up. According to data from Legambiente, over the last six years, from 2020 to 2025, the average surface temperature of the Mediterranean Sea between May and September each year has never fallen below 24°C. Inland, however, among the lakes suffering most from prolonged drought and high temperatures, are Lake Iseo – which lost more than 79 per cent of its water volume in just 42 days, from 12 June to 24 July – and Lakes Maggiore and Como, which lost 76 per cent. Another serious threat is the dumping of waste at sea, a scourge that spares not even the seabed. For example, in Polignano a Mare at the end of July, Goletta Verde, together with local divers and as part of its long-running ‘Puliamo il Mondo’ campaign, recovered around 30 abandoned tyres from the sandy seabed.
Wastewater treatment, PNACC and offshore wind power
The state of our seas and lakes serves as a litmus test for Italia’s major unresolved issues, such as inadequate wastewater treatment – a problem we have been highlighting for 40 years now through the Goletta Verde and for over 20 years through the Goletta dei Laghi. The picture painted by the Golette’s findings confirms, in short, the urgent need to tackle the root causes, starting with inadequate wastewater treatment and making up for Italia’s delays. Legambiente points out that four infringement proceedings are currently pending against the Italian Peninsula for failure to comply with the European Urban Waste Water Directive (91/271): to date, the first two have cost over 200 million euros. Furthermore, under the new Waste Water Directive (2024/3019), the country’s treatment plants will have to adapt to the new requirements, at an estimated cost of between 645 million and 1.5 billion euros for the larger plants alone.
Wastewater treatment plants
This is why Legambiente believes it is urgent to improve the efficiency of urban wastewater treatment plants by allocating more resources, to work on the collection of untreated effluent, and to combat illegal discharges into surface waters. These are proposals that the environmental organisation is reiterating today, alongside a national plan for wastewater treatment, calling also for a review of the Bathing Water Framework Directive with a focus on monitoring points, as well as a strengthening of information and awareness-raising campaigns. It should not be forgotten that tackling the climate crisis also involves the sea and lakes through further mitigation and adaptation measures, starting precisely with the allocation of the financial resources needed to implement the National Climate Change Plan (PNACC), the development of a National Plan for the specific adaptation of coastal areas to the climate crisis, and the creation of new marine and terrestrial protected areas.
